Flask



FIG. 1 is a bottom plan view of a flask showing my new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a front elevation view thereof;

FIG. 4 is a top perspective view thereof;

FIG. 5 is a top perspective view thereof, shown in the open position with the closure portion removed;

FIG. 6 is a bottom perspective view of the closure portion of the flask of FIG. 1; and,

FIG. 7 is a cross-section view of the claimed design taken along the line 7-7 in FIG. 3. 

The ornamental design for a flask, as shown and described. 